/*
* Copyright 2008-2010 the original author or authors.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package org.codehaus.groovy.transform;
import groovy.transform.EqualsAndHashCode;
import org.codehaus.groovy.ast.ASTNode;
import org.codehaus.groovy.ast.AnnotatedNode;
import org.codehaus.groovy.ast.AnnotationNode;
import org.codehaus.groovy.ast.ClassHelper;
import org.codehaus.groovy.ast.ClassNode;
import org.codehaus.groovy.ast.FieldNode;
import org.codehaus.groovy.ast.MethodNode;
import org.codehaus.groovy.ast.Parameter;
import org.codehaus.groovy.ast.expr.*;
import org.codehaus.groovy.ast.stmt.BlockStatement;
import org.codehaus.groovy.ast.stmt.EmptyStatement;
import org.codehaus.groovy.ast.stmt.ExpressionStatement;
import org.codehaus.groovy.ast.stmt.IfStatement;
import org.codehaus.groovy.ast.stmt.ReturnStatement;
import org.codehaus.groovy.ast.stmt.Statement;
import org.codehaus.groovy.control.CompilePhase;
import org.codehaus.groovy.control.SourceUnit;
import org.codehaus.groovy.syntax.Token;
import org.codehaus.groovy.syntax.Types;
import org.codehaus.groovy.util.HashCodeHelper;
import java.util.List;
import static org.codehaus.groovy.transform.AbstractASTTransformUtil.*;
@GroovyASTTransformation(phase = CompilePhase.CANONICALIZATION)
public class EqualsAndHashCodeASTTransformation extends AbstractASTTransformation {
static final Class MY_CLASS = EqualsAndHashCode.class;
static final ClassNode MY_TYPE = new ClassNode(MY_CLASS);
static final String MY_TYPE_NAME = "@" + MY_TYPE.getNameWithoutPackage();
private static final ClassNode HASHUTIL_TYPE = new ClassNode(HashCodeHelper.class);
private static final Token ASSIGN = Token.newSymbol(Types.ASSIGN, -1, -1);
private static final ClassNode OBJECT_TYPE = new ClassNode(Object.class);
public void visit(ASTNode[] nodes, SourceUnit source) {
init(nodes, source);
AnnotatedNode parent = (AnnotatedNode) nodes[1];
AnnotationNode anno = (AnnotationNode) nodes[0];
if (!MY_TYPE.equals(anno.getClassNode())) return;
if (parent instanceof ClassNode) {
ClassNode cNode = (ClassNode) parent;
checkNotInterface(cNode, MY_TYPE_NAME);
boolean callSuper = memberHasValue(anno, "callSuper", true);
if (callSuper && cNode.getSuperClass().getName().equals("java.lang.Object")) {
addError("Error during " + MY_TYPE_NAME + " processing: callSuper=true but '" + cNode.getName() + "' has no super class.", anno);
}
boolean includeFields = memberHasValue(anno, "includeFields", true);
List<String> excludes = tokenize((String) getMemberValue(anno, "excludes"));
createHashCode(cNode, false, includeFields, callSuper, excludes);
createEquals(cNode, includeFields, callSuper, excludes);
}
}
public static void createHashCode(ClassNode cNode, boolean cacheResult, boolean includeFields, boolean callSuper, List<String> excludes) {
// make a public method if none exists otherwise try a private method with leading underscore
boolean hasExistingHashCode = hasDeclaredMethod(cNode, "hashCode", 0);
if (hasExistingHashCode && hasDeclaredMethod(cNode, "_hashCode", 0)) return;
final BlockStatement body = new BlockStatement();
List<FieldNode> list = getInstancePropertyFields(cNode);
if (includeFields) {
list.addAll(getInstanceNonPropertyFields(cNode));
}
if (cacheResult) {
final FieldNode hashField = cNode.addField("$hash$code", ACC_PRIVATE | ACC_SYNTHETIC, ClassHelper.int_TYPE, null);
final Expression hash = new VariableExpression(hashField);
body.addStatement(new IfStatement(
isZeroExpr(hash),
calculateHashStatements(hash, list, callSuper),
new EmptyStatement()
));
body.addStatement(new ReturnStatement(hash));
} else {
body.addStatement(calculateHashStatements(null, list, callSuper));
}
cNode.addMethod(new MethodNode(hasExistingHashCode ? "_hashCode" : "hashCode", hasExistingHashCode ? ACC_PRIVATE : ACC_PUBLIC,
ClassHelper.int_TYPE, Parameter.EMPTY_ARRAY, ClassNode.EMPTY_ARRAY, body));
}
private static Statement calculateHashStatements(Expression hash, List<FieldNode> list, boolean callSuper) {
final BlockStatement body = new BlockStatement();
// def _result = HashCodeHelper.initHash()
final Expression result = new VariableExpression("_result");
final Expression init = new StaticMethodCallExpression(HASHUTIL_TYPE, "initHash", MethodCallExpression.NO_ARGUMENTS);
body.addStatement(new ExpressionStatement(new DeclarationExpression(result, ASSIGN, init)));
for (FieldNode fNode : list) {
if (fNode.getName().contains("$")) continue;
// _result = HashCodeHelper.updateHash(_result, field)
final Expression fieldExpr = new VariableExpression(fNode);
final Expression args = new TupleExpression(result, fieldExpr);
final Expression current = new StaticMethodCallExpression(HASHUTIL_TYPE, "updateHash", args);
body.addStatement(assignStatement(result, current));
}
if (callSuper) {
// _result = HashCodeHelper.updateHash(_result, super.hashCode())
final Expression args = new TupleExpression(result, new MethodCallExpression(VariableExpression.SUPER_EXPRESSION, "hashCode", MethodCallExpression.NO_ARGUMENTS));
final Expression current = new StaticMethodCallExpression(HASHUTIL_TYPE, "updateHash", args);
body.addStatement(assignStatement(result, current));
}
// $hash$code = _result
if (hash != null) {
body.addStatement(assignStatement(hash, result));
} else {
body.addStatement(new ReturnStatement(result));
}
return body;
}
public static void createEquals(ClassNode cNode, boolean includeFields, boolean callSuper, List<String> excludes) {
// make a public method if none exists otherwise try a private method with leading underscore
boolean hasExistingEquals = hasDeclaredMethod(cNode, "equals", 1);
if (hasExistingEquals && hasDeclaredMethod(cNode, "_equals", 1)) return;
final BlockStatement body = new BlockStatement();
Expression other = new VariableExpression("other");
// some short circuit cases for efficiency
body.addStatement(returnFalseIfNull(other));
body.addStatement(returnFalseIfWrongType(cNode, other));
body.addStatement(returnTrueIfIdentical(VariableExpression.THIS_EXPRESSION, other));
body.addStatement(new ExpressionStatement(new BinaryExpression(other, ASSIGN, new CastExpression(cNode, other))));
List<FieldNode> list = getInstancePropertyFields(cNode);
if (includeFields) {
list.addAll(getInstanceNonPropertyFields(cNode));
}
for (FieldNode fNode : list) {
if (excludes.contains(fNode.getName()) || fNode.getName().contains("$")) continue;
body.addStatement(returnFalseIfPropertyNotEqual(fNode, other));
}
if (callSuper) {
Statement result = new IfStatement(
isTrueExpr(new MethodCallExpression(VariableExpression.SUPER_EXPRESSION, "equals", other)),
new EmptyStatement(),
new ReturnStatement(ConstantExpression.FALSE)
);
body.addStatement(result);
}
// default
body.addStatement(new ReturnStatement(ConstantExpression.TRUE));
Parameter[] params = {new Parameter(OBJECT_TYPE, "other")};
cNode.addMethod(new MethodNode(hasExistingEquals ? "_equals" : "equals", hasExistingEquals ? ACC_PRIVATE : ACC_PUBLIC,
ClassHelper.boolean_TYPE, params, ClassNode.EMPTY_ARRAY, body));
}
}